HOUSTON — In the first of two debates between U.S. Senate candidates on Tuesday night, Democrat Paul Sadler, set off an hour-long fusillade of charges, insults and invective against his vastly better-known and better-funded Republican rival, Ted Cruz.

The race pits Cruz, a former Texas solicitor general, against Sadler, a former state representative and East Texas trial lawyer for the seat being vacated by retiring U.S. Sen. Kay Bailey Hutchison.

The hour-long event was carried live only on WFAA-TV in Dallas. Trailing Cruz by more than 25 points in the most recent poll and with little to lose, Sadler was on the attack from the opening question. An early exchange was typical:

“Part of the philosophy of President Obama and this administration is trying to get as many Americans as possible dependent on government so the Democrats can stay in power in perpetuity,” Cruz said.

“That's the craziest thing I've ever heard in my life,” Sadler responded. “You are really accusing the president of the United States of using a government program to manipulate people to not get a job, to be dependent on government for services. ... That's just crazy, Ted. It's crazy.”

Cruz replied, “I'm impressed that we're a few minutes into it and you've already called me three times crazy on observing that the president has expanded government dependency.”

The invective continued apace, with Sadler suggesting at one point that Cruz was a troll.

Several times during the debate, a visibly angry Sadler accused Cruz of lying. At times he laughed derisively while Cruz responded to a question.

SMU political scientist Cal Jillson said he watched the full debate and wished he had his money back. Sadler, he said, “is way back in the polls and does not have the money to get up on TV to get his message. That made him treat the debate as his one chance to challenge Cruz, and he came off as a bit frantic.”

Cruz, the former state solicitor general and already a star among tea party adherents nationwide, generally stayed calm and stuck to his campaign talking points. Seeking at every opportunity to tie his Democratic rival to President Barack Obama. he said Sadler was “unapologetically liberal,” a supporter of gay marriage and a believer in Obama's Affordable Care Act.

“Cruz was more combative than I thought he would be,” said Rice University political scientist Mark Jones, “but I think that was in large part due to Sadler's strategy of trying to portray him as an extreme conservative, which at some point required him to respond in a more aggressive manner. I think at some point it also got under his skin a little bit, which I hadn't seen with the (Lt. Gov. David) Dewhurst debates.”

Jones said he saw advantages for both candidates from the Tuesday night confrontation.

“For Cruz, all he needs to do is not have an epic meltdown, and if he does that, then he's fine, because we're a red state, a state where he's winning the election, where his opponent is under-financed. As long as he doesn't do anything to repel voters, he will win the race,” Jones said.

Sadler, he said, took advantage of a rare opportunity to reach a statewide audience, both in the debate and in the media coverage afterward.

“And he also demonstrated that he is a credible candidate. He's not a gadfly candidate,” Jones said. “He is somebody who would be a very respectable U.S. senator were he to have that opportunity, albeit extremely unlikely.”

In the nonpartisan Texas Lyceum survey released a few hours before the debate, Cruz led Sadler 50 percent to 24 percent, with 26 percent saying they were still undecided.

Cruz and Sadler meet again in an Oct. 19 debate from KERA-TV, the Dallas PBS station.